Balbo: L. Cornelius Balbus, a native of Gades, who had received Roman citizenship for his services against Sertorius; cf. Cic. pro Balbo, 5 f. He attached himself closely to Caesar, and was often Caesar's confidential agent in Rome. We have three of his letters to Cicero, Att. 9.7A, 7B, and 13A.
M. Iteium: nothing is known of him. See Crit. Append.
Leptae: Q. Lepta held some minor position under Caesar at this time. Fam. 6.18 and 19 are addressed to him.
sustulimus manus: a gesture of surprise.
invitatu: apparently used nowhere else. Parallel forms, however, as Tyrrell remarks, are involatus (Ep. LXV. 7), reflatus (Att. 12.2.1), itus (Att. 15.5.3).